Bumper



1935- v. P.WILLIAM$ 2,031,349

BUMPER Filed Jan. 8, 1955 4 Sheets-Sheet 1 Feb. 18, .1936.

V. P. WILLIAMS 2,93L349 BUMPER Filed Jan. 8, 1955 4 Sheets-Sheet 2 d /9 59 A J7 9 r r A r 58 519 W7 3 6/ /9 6? 7i 1 51 A J Y \Y i l 1/ Feb 18, 1936,

v. P. WILLIAMS ZMELWW BUMPER Filed Jan. 8, 1955 4 Sheets-Sheet 3 /6 i W W WLS/ x l r A was Mae Patented Feb. 18, 1936 UNW'ED gTATES BUMYPER.

Villor P. Williams, Baltimore, Md., assignor to Estelle Williams Gomborov, Baltimore, Md.

Applicationlanuary 8, 1935, Serial No. 929

22 Claims.

This invention relates to vehicle bumpers and is an improvement over the bumper construction shown in my prior Patent No. 1,957,515, granted May 8, 1934 as well as a continuation in part of my copending application Serial No. 724,402 filed May 7, 1934. This invention is furthermore an improvement over the subject matter disclosed in my other copending application Serial No. 755,821 filed Dec. 3, 1934.

Both in my prior patent and in my first mentioned application I have shown a bumper comprising a main or impact receiving bar and a back bar provided with spring arms that slidably engage thev main bar. In my prior patent the main bar was provided with means acting to guide the spring arm in its sliding movement relative to the main bar. In my first mentioned copending application there was provided in addition to the guiding means, resilient means which functioned to produce a frictional resistance to the sliding and vibratory movements of the spring arms.

The invention set forth in my latter copending application relates to the employment of various provide the necessary frictional resistance to the sliding and vibratory movements of the spring arms but also to add a supporting strength to the shock absorbing characteristics of the spring arms. In, each of these copending applications the slidable ends of the spring arms frictionally engage flat plane surfaces on the main bar that are substantially parallel to the plane of the main bar, the resilient means in each case acting normal to the spring arms and to the surfa es on which the same slide.

It is accordingly the main object of this inven tion to employ in addition to the static frictional resistance set up by the above mentioned resilient means an additional resistance imparted to the ends of said spring arms directed along the plane of said spring arms which resistance may be produced either by a cam surface over which the ends of the spring arms slide on by the provision of a resilient medium adapted to be directly engaged and compressed by said spring arm ends.

Another object of this invention resides in the functioning of the spring arm as a reinforcing means for the main bar as the same is actuated by impacts.

The above specified objects along with those set forth in my latter copending application as well as other objects of this invention, will become, apparent as the description thereof given forms of resilient means designed not only to hereunder proceeds, reference being now had to the accompanying drawings in which like parts have the same reference characters and wherein:-

Fig. 1 is a plan view of a. bumper construction showing double spring arms connected to the main bar by a single housing.

Fig. 2 is a partial central rear elevational view of the bumper showing the housing.

Fig. 3 is a plan view of a modified form of bumper construction wherein each spring arm is connected to the main bar by an individual housing.

Fig. 4 is a plan view of a modified form of bumper construction wherein the spring arms are carried by the main bar and-each connected by an individual housing to the vehicle frame.

Fig. 5 is a partial sectional view taken on line 55, Fig. 2, in the direction of the arrows.

Fig. 6 is a view similar to Fig. 5 showing a modified construction employing helical springs.

Fig. 7 is a view similar to Fig. 5 showing a modification thereof.

Figs. 8, 9, 10, 11 and 12 illustrate modified forms of spring arms and connections therefor; Fig. 10 being a detail sectional view of Fig. 9, and Fig. 12 being a sectional view taken on line !2-i2, Fig, 11.

Fig. 13 is a view similar to Fig. 5 showing a rubber spring and cam construction.

Fig. 14 shows in an individual spring arm connection, a rubber spring assembly.

Fig. 15 shows in a double spring arm connection a volute and rubber spring arrangement.

Fig. 16 is a sectional view taken on line 16-46,

' Fig. 15.

Fig. 17 shows a modification of the connection shown in Fig. 15.

Fig. 18 shows in a double spring arm connection, an eccentric mounting for the spring arm ends.

Figs. 19, 20, 21, 22, 23 and 24 show various embodiments of a still further modified manner of mounting the spring arm ends by a pin and slot connection to a cam member; Fig. 22, being a sectional view taken on line 22 22, Fig. 21, and Fig. 24 being a sectional view taken on line 24-24, Fig. 23.

Figs. 25, 26 and 27, respectively, show diagrammatically, the force distribution on the bumper elements in the normal relationship of parts and under an impact received thereby.

In Fig. 1 there is shown a complete bumper embodying my invention which bumper comprises an impact or main bar I and back bars 2, the outer ends thereof being connected to the main bar I in any suitable manner as at 3. The back bars 2 are formed with oppositely disposed spring arms 4, the ends of which are disposed within a housing 5 for slidable engagement with a surface on said main bar arranged Within said housing all in a manner to be hereinafter described.

The form of bumper shown in Fig. 3 differs from that of Fig. 1 only in that each spring arm 4 is provided with an individual housing 6. Both the bumpers of Figs. 1 and 2 are mounted on the frame horns I and are connected thereto in any suitable manner as by the bolts 8.

In Fig. 4, the main bar I has the ends thereof secured to the frame horns I, which ends also carry the housings It. In this form of construction the spring arms 4 are carried by the main bar I being secured thereto at one end as at I I, the other end thereof being disposed within the housing ID for sliding engagement with a surface arranged therein,

The three forms of bumpers illustrated in Figs. 1, 3 and 4 are merely illustrative of conventional forms of bumper design, the herein described invention residing solely in the connections contained in the housings5, 6 and III which include means for not only retaining the spring arms 4 and 4 in frictional sliding engagement on suitable surfaces arranged within the housings but also in the provision of additional means within the housing for imposing a resistance to the endwise movement of said spring arms. In my copending application Serial No. 755,821 filed December 3, 1934, there has been disclosed a variety of resilient units which act in a direction normal to the spring arms to produce a frictional resistance to the sliding movement of the same. It is accordingly desired understood, that I contemplate the use of any one of the resilient units described in said copending case in the herein to be described housing connections for use as the above indicated means therein for retaining the spring arms 4 and 4 in frictional sliding engagement with the surface arranged within said housing. I

The description of the various forms of housing connections embodying the present invention will now be set forth.

The housing connection in Fig. 5 comprises a substantially four sided tubular housing I5 provided with open ends I6. Arranged centrally within the housing I5 is a cam block I! provided with a bore I8 through which the bolt I9 extends to attach the housing I5 to the main bar I. The cam block I 1 acts as a spacer element to prevent buckling of the walls of the housing by the clamping pressure exerted to the nut on the bolt I9. Arranged adjacent the Wall 2| of the housing that contacts the inner side of the main bar I is a wear plate 23 formed of any suitable material and which is clamped in position by the cam block I1 and any other suitable means not shown.

Extending within the housing I5 are the spring arms 4 the end portions thereof being adapted to slidably engage the wear plate 23. As the connections on each side of the housing are identical, only one side thereof shown in detail will be described. This will be done with all other double spring arm connections to be described hereinafter.

To retain the slidable end portion 4 of the spring arm in frictional engagement with the wear plate 23 there is provided a laminated spring 24 held against longitudinal bodily movement with respect to the housin I5 by the bosses 25 thereon that cooperate with the slots 25 formed in the sides of the laminated spring. A bearing element or button 27 is carried by the spring 24 for bearing engagement with the adjacent side of the spring arm end 4'.

The cam block I! is provided with two cam surfaces 39 of a concave curvature that extends from a point substantially adjacent the end of the slidable spring arin portion 4* and the front housing wall 2|, to the rear wall 21 of the housing I5. The design of the cam surface 30 is such that after a slight inward movement of the spring arm end 4 under an impact received by the bumper, the end of the spring arm will engage the cam surface 39 for sliding movement thereon. In view of the resistance set up by the cam surface 30 to the progressive movement of the spring arm end 4 inwardly of the housing, the pring arm will be flexed in such a manner as to not only reinforce the main bar I but also to bring about the maximum shock absorption possible. A detail analytic discussion with reference to this flexure with respect to this form as well as with reference to the other forms to be described will be given hereinafter.

While this form of construction utilizes a wear plate 23, it is to be understood that the use of the same is entirely optional in this instance as well as in all the other modified forms of connection to be described hereinafter.

In the form of connection shown in Fig. 6, the housing is preferably made in the form of a casting having a front wall 36, a rear wall 31, side wall 38 and end walls 39 that are spaced from the front wall 36 to provide openings 40.

Integrally formed with the housing 35 is a cam block 4| provided with the cam surfaces 42, said cam surfaces merging with the inner surface of the front wall 36.

Extending within the housing 35 through the openings 40 are the end portions 4 of the spring arms 4, which slidably engage the front wall 36. To retain the spring arm end 4 in frictional engagement with the wall 35 there is provided a coil spring arranged transversely within the housing 35 and normal to the spring arm end 4 A spring seat 46 constituting a bearing element is carried by the forward end of the coil spring 45 and contacts the spring arm end 4. The rear end of the coil spring 45 is seated within a suitable recess provided therefor in the rear wall 31 of the housing 35. In this particular form the rear wall 31 is provided with threaded openings 41 in each of which is threadedly mounted a cup shaped spring seat 48 in which the rear end of the coil spring 45 is positioned. This construction facilitates the assembly of the spring 45 within the housing and also permits an adjustment in the compression thereof. The housing 35 is secured to the main bar I by the center bolt I9. In view of the depth of the cup seat 48,

bodily movement of the coil spring 45 with respect to the housing 35 is positively prevented.

The modified form of housing connection shown in Fig. 7 is somewhat similar to that shown in Fig. 5. In this case the housing 50 is formed as a channel shaped stamping having side walls 5|, and a rear wall 52, that is curved towards the ends of the housing but terminates short thereof to form the openings 53, as clearly shown. Arranged longitudinally within the housing 50 is a cam member 55, provided with similar curved cam surfaces 56 that extend outwardly from the center portion of the rear wall 52 of the housing to the ends thereof. The end portions of said cam surfaces being substantially fiat as at 51, and constituting in effect a front wall of said housing. The central portion of the cam member 55 is preferably flattened as at 58 and is secured to the rear Wall 52 of the housing in any suitable manner as by the welds 59 Aligned openings are respectively provided in the central portion 58 and rear wall 52 for the reception of the bolt l9 which attaches the housing to the main bar I. In order to prevent buckling of the walls of the housing, the bolt I9 may be provided with a spacer sleeve 59*. The cam member is preferably made of flat spring stock of a width substantially equal to the distance between the side walls of the housing so as to snugly fit therebetween, the flat portions 5'! thereof being adapted to engage the rear surface of the main bar I.

tionally retained in position by the laminated leaf spring 59, similar in form to the spring 24 shown in Fig. 5. The outer end of the spring 59 engages an abutment 60 formed on the rear wall 52 of the housing 50, the inner end thereof being normally spaced from the cam member 55 in order that endwise movements of the spring 59 be permitted. In the assembly of the spring 59 within the housing, the same is placed under compression and in view of the mounting thereof, as shown, is positively retained therein.

In Fig. 8, the connection comprises a channel shaped housing 50 provided with the side walls 6! and bottom wall 62. Formed centrally on the bottom wall 62 and extending between the side walls 5i is an inwardly directed transverse boss 63 on which is seated the indented portion 64 of the cam member 65, to positively center said cam member within the housing. The cam member 65 is provided with similar cam surfaces 66 that extend towards the ends of the housing for engagement with the rear surface of the main bar which said housing 69 is attached by the bolt 69, the nut 29 thereof being positioned within the boss 53. A spacer sleeve 61 may be provided if desired in surrounding relation to the bolt l9.

Preferably the cam member 65 is made of flat heavy spring stock of a width equal to the distance between the side walls 6| so as to snugly fit therein, the end portions being tapered as at 68 in order to reduce the clearance between the spring arm 4 and the rear surface of the main bar I.

The end portion of the spring arm 4 is bowed as at 4 to provide spaced surfaces 69 and H1 adapted to slidably engage the cam surface 66 adjacent the other end thereof. The bowed portion i is also adapted to have bearing engagement with a wear plate H provided on the bottom wall 62. In the assembly of the parts comprising this connection, the spring arm end i is normally maintained in frictional engagement, both with the cam surface 66 and the wear. plate H Movement of the bowed end 4 inwardly will be frictionally resisted by the cam surface 66 as the same causes fiexure of the spring arm 4.

In the connection shown in Fig. 9, the housing 15 is of channel form, and constitutes the side walls 15. and bottom wall Tl. Arranged within the housing i5 is a spring leaf I8, provided with a central convex portion 1'9, formed between concave portions 89, the end portions 3i being bowed inwardly in opposed relation, each end portion terminating in an outwardly directed abutment 82. The spring leaf [8 is preferably formed of flat highly resilient spring stock and has formed on the convex portion 19.9.11 opening,

through which the bolt i9 projects in attaching curved and adapted to slidably contact the wear plate 23. Immediately adjacent the end of the spring arm there is provided a tongue-like projection preferably struck out of the body of the spring arm, see Fig; 10, which projection is adapted to extend through a suitable opening 99 7 provided in the spring leaf end portion 85, the

end of said spring arm abutting the upstanding abutment 82. To look the ends of the spring arm and leaf spring together there is provided a cotter-pin or any other suitable fastening means 8'3.

The spring arm end i is maintained in frictional sliding engagement with the wear plate 23 by the spring leaf F3, which in view of the initial compression thereon reacts through the looped K portion 8! to resiliently urge the spring armend 4 against the wear plate 23 with a pressure sufficient to produce the desired frictional, resistance. Movement of the spring arm end 4 inwardly into the housing is not only resisted by the friction set up by the leaf spring I8 but also by its resilient action as the same is deflected in View of the connection therebetween. The resistance to deflection set up by the spring iii and its effect on the spring arm 5 is the same as that produced by the cam surface in the connections hitherto described.

In all the preceding forms of connections a resilient medium has been employed to urge the spring arms against a surface supported by the main bar and positioned between said spring arms and the housing enclosing the same. In the form of connection shown in Figs. 11 and 12, the resilient medium is interposed between the main bar and the cam surface which is urged into frictional engagement with the spring arm sliding thereon.

The housing 98 of Fig. 11 is somewhat box shaped and comprises the side walls es, bottom wall 92 and end wall 93 provided with openings 94. Arranged within the housing 99 is a cam member 95 similar in form to the cam member 55 shown in Fig. '7, differing therefrom only in that'the end portions of the cam surfaces 95 are spaced from the main bar 5, said cam member 95 being preferably fastened to the central portion of the wall 92 by welds 9! or any other suitable fastening means, and provided with a bolt opening 99. Fitted within the area defined by the cam member 95 and the side walls of the housing 99 is a rubber block ifiil. provided with a central transverse bolt opening lei. The housing 99, cam member 95 and rubber block we are atcached to the main bar I by the bolt 59, the initial size of the rubber block being such that the same is placed under an initial compression. If desired additional bolts 682 may be employed at the ends of the housing.

Extending into each of the openings 96 in the ends of the housing 99 are the spring arms i, the end portions 4' being adapted to slidably frictionally engage the cam surfaces 95. Preferably the spring arm end i is formed with a projecting cup shaped seat I03 which acts as a raceway for the roller bearings I04 seated therein adapted to have bearing engagement on the wall 92 of the housing 90. At each of the ends of the wall 92 there is provided a stop I05 to limit outward movement of the spring arm ends 4 The surface of the rubber block I adjacent the main bar I is formed with corrugations I06 to permit the rubber to flow as the same is additionally compressed by the movement of the spring arm end 4 on the cam surface 96. Referring to Fig. 12, it will be noticed that the width of the cam member 95 is slightly greater than that of the spring arm end 4 and less than the width of the housing so that in effect the cam surface 96 floats on the compressed rubber block I 00. The pressure exerted by the rubber block I 00 is sufficient to maintain the frictional engagement of the spring arm end 4 on the cam surface 96 and at the same time maintain the rolling engagement of the rollers I04 on the wall 92. Thus, inward movement of the spring arm ends 4 under impacts received by the bumper will be yieldingly resisted by the cam member 95 and rubber block I00 as well as by the frictional resistance set up by the sliding movement of the spring arm end 4 on the cam surface 96.

Figs. 13 and 14 illustrate specific forms of connections employing rubber blocks as the resilient medium, cooperating with cam members.

In Fig. 13, the housing H0 is in the form of a box provided with opening I I I at the ends thereof. The bottom wall of the housing is formed with a central interiorly directed boss I I2 extending transversely of the housing to define spaced seats II3. A cam member II4 similar to the cam member 55, Fig. '7 is provided with cam surfaces H5 and is secured to the boss II2 by the welds H6 or any other suitable fastening means, both the cam member and the boss having aligned openings II! to permit the insertion of the bolt I9 which secures the housing IIO to the main bar I. The cam surfaces II 5 are suitably curved, the outer ends thereof being adapted to engage the rear surface of the main bar I.

Extending through the openings III are the end portions 4 of the sprin arms ea h of which is adapted to frictionally slidably engage a cam surface II5. To maintain this frictional engagement there is provided rubber blocks II8 molded in the form of a parallelogram. One end of the rubber block unit is seated in locked engagement within the seat II 3 provided in the housing IIO, the other end of said rubber block engaging the slidable end portion 4 of the spring arm 4 and held in locked engagement thereby, by the abutments II 9 and I20, said rubber block I I8 being normally under an initial compression.

Movement of the slidable spring arm ends I inwardly will deform the rubber blocks I I8 in such manner as to offer a progressive increase in the pressure the same exerts on said arm ends 4 in the production of the frictional resistance offered to the sliding movement of said arm ends 4 on the cam surface I I5. This in addition to the resistance set up as the arm ends 4 slide over the cam surfaces II5, constitute an exceedingly efficient shock absorption medium for the impacts delivered on the bumper.

If desired the area defined by the cam member H4 and the side walls of the housing IIO may be filled by a rubber block I2I indicated by the dotted lines in Fig. 13.

In Fig. 14, the housing I23 is of box-like formation and of a size sufiicient to accommodate the sliding end of one spring arm 4 which enters the housing through the opening I 24, said housing being secured to the main bar or supporting member I by the bolts or rivets I25. Fitted within the housing I23 is a cam member I26 provided with the cam surface I21 and so arranged as to extend diagonally with the housing, one end thereof being fastened to the bottom wall of the housing as by the Weld I28, said end being furthermore provided with an abutment I29. The other end of said cam member is adapted to engage the rear surface of the main bar I adjacent the opening I 24 in the housing. The end portion 4 of the spring arm 4 slidably engages the cam surface I21 and is frictionally retained in contact therewith by the rubber block I30, one end of which is locked to the housing I23 by the cam abutment I and housing shoulder I3I as clearly shown, the other end thereof abutting the spring arm end 4 The general form of the rubber block I30 and its operation is similar to that of the rubber block I I8 shown in Fig. 13. If desired the cam member I26 which is preferably formed of flat spring stock, may be backed up by a rubber block I32, to increase the rigidity of the structure.

Another method of imposing such endwise resistance to the inward movement of the spring arms consists in the provision of a resilient means adapted to be compressed by the end of said spring arms. Such a construction is shown in Figs. 15, 16, 17 and 18.

Referring to Figs. 15 and 16 there is shown a tubular housing I rectangular in cross-section disposed with its front side wall I 36 adjacent the main bar I, the rear side wall I 37 being provided adjacent each end thereof with a circular recess I38. Extending through the open end of the housing I35 is the end portion 4 of the spring arm 4 adapted to slidably engage the front wall I36 of the housing, the end of the portion 4 being formed with an abutment I39 of a width sufficient to fit between the walls I36 and I3! without binding. To maintain the frictional engagement of the end portion 4 with the surface of the wall I36 there is provided a volute spring I40 adapted to be seated within the recess I38, the small end convolution carrying a wear button I M adapted to abut the spring arm end 4 Disposed between the opposed abutments I39 at the end of the spring arms 4 is a rubber block I42 provided with a central opening I43 and concaved depressions I44 in the side walls I45 thereof for a purpose to be hereinafter described. At

each end of the rubber block I42 there is arranged a follower plate I46 adapted to be engaged by the abutment I39.

The housing I 35 is attached to the main bar I by the center bolt I9 and if so desired, by the end bolts I41, the bolt I9 passing through the opening I43 in the rubber block I42 to lock the same within the housing. It is obvious from the above construction that sliding movement of the spring arm end 4 is resisted in two ways. First, to the functional resistance produced by the pressure executed by the volute spring I40 and secondly by the resiliency of the rubber block I42, the depressions I44 thereof permitting compression of the rubber block to accommodate said movement. This resistance, particularly to the endwise movement of the spring arm end 4 will produce an added flexure or deflection of the spring arm 4 to reinforce the main bar I as will be described in greater detail hereinafter. In

view of the compactness of this form of construction, and high capacity of the volute spring there is produced a highly satisfactory and efficient shock absorbing connection of comparatively little cost.

If desired there may be interposed between the spring arm end 4 and wall I36 a wear plate such as 23 previously described.

In Fig. 17, the connection shown is similar to that of Fig. 15 except that the volute springs have been omitted. In this construction the housing I58 is of channel form the bottom wal1'I5I thereof being provided with inwardly curved ends I52 that terminate short of the housing ends to define an opening I53 at each end thereof. Gentrally arranged within the housing I58 is a rubber block I54 identical with the rubber block I82 in Fig. 15, said block and housing being attached to the main bar I by the bolt I9. Positioned adjacent the rear surface of the main bar I be tween the same and the rubber block I58 is a wear plate 23 adapted to be slidably engaged by the end portion 4 of the spring arm 4 disposed within the housing I58. The end M of the spring arm i is provided with a reversely bent loop I55 that exerts a spring action on the wall II to maintain the frictional engagement of the end portion 4 on the Wear plate 23. The portion I55 of the loop I55 acts as an abutment against the follower plate I51 interposed between the rubber blockI54 and said abutment.

A more elaborate form of connection is shown in Fig. 18, which comprises the substantially channel shaped housing I88, having side walls I8! and a bottom wall I82. The end portion of the spring arm 4 disposed within the housing, in this case comprises a spring eye 5 that is preferably maintained as a closed cylinder by the Weld I68. Fitted within the eye 4 is a bearing sleeve I84 adapted to have rotatably mounted therein an eccentric I85 which in turn is rotatably mounted on the bolt or pin I56 rigidly supported in any suitable manner, not shown by the side walls I8I of the housing I68.

Supported within the housing I88 is a rubber block I81, provided with the central opening I88 through which the bolt I9 extends to attach the same and the housing I88 to the main bar I, said block extending between the opposed spring arm eyes 4*. Arranged between the eye 4 and the ends of the rubber block I6? is a combined wear and follower member I88, one end I89 of which slidably engages the bottom wall I82 of the housing. The follower I88 encircles that portion of the eye 4 immediately adjacent the rubber block I81, extending rearwardly of the eye as at l'iII with the other end terminating at the opening in the housing as clearly shown. The wear portion I18 of the follower is spaced from the main bar I, there being interposed therebetween a rubber strip I! I, preferably integral with the main body of the rubber block I61. The rubber strip I'II may be additionally provided with a bearing cap I12.

The normal relationship of the parts is as shown in Fig. 18, the initial compression of the rubber block I81 being such as to maintain the eccentric I85 and spring arm eye 4 in the position shown. It is intended that the arc of movement of the eccentric be through the angle X, during which movement the spring arm eye l and follower I58 will move inwardly to compress the rubber block I81. During this movement considerable frictional resistance will be set up between the spring arm eye 4 and the follower I68, as the eye 4* is rotated to accommodate the deflection of the spring arm 4 under impacts received by the main bar I of the bumper. An additional frictional resistance is produced by the movement of the cap I12 on the rear surface of the main bar I, inasmuch as the same is constrained to move simultaneously with the follower portion I10. It is thus seen that shocks received by the spring arms 8 which are deflected thereunder are effectively absorbed by the two frictional resistances as above set forth in addition to the endwise compression of the rubber block I82. This form of mounting is especially adaptable as an individual connection for a single spring arm to a suitable supporting member, such as indicated in Figs. 3 and 4.

It is to be understood that in the proper design of the construction shown in Fig. 18, the throw of the eccentric I55 should be sufiicient to accommodate practically the maximum movement which the end of the spring arm 4 would have under normal deflection of. the same.

In some cases it has been found that the use of the housing as a retaining member may be altogether dispensed with. In Figs. 19 to 24 there are shown typical constructions embodying this thought.

In Fig. 19 there is shown a unitary cam member I88 formed as a casting provided with similar curved cam surfaces I8! formed on the cam walls I82. The cam walls I82 branch outwardly from a central thickened bolt receiving portion I83 provided with the bolt opening I84, through which the bolt I85 extends to attach the cam member I88 to the main bar I. The ends of the cam walls I82 are provided with leg portions I88 which are secured to the main bar I by the bolt I81.

Each ofthe cam walls I82 is formed with a centrally located longitudinally extending slot I88. Arranged for sliding movement on the cam surfaces Hill of the cam walls I82 are the ends of the spring arms 8. Inwardly of the end of. each spring arm 4 there is provided an opening I89 in registry with the slot I88. A bolt I98 with its head I9I seated on the inner surface of the cam wall I82 extends through the slot I88 and opening I89. To maintain the end of the spring arm in frictional engagement with the cam wall I82, there'is fittted on the bolt the spring plate I92, retained under compression by the nut I93 on the bolt I98. If desired there may be placed within the slot I88, a wear sleeve I98 turnably mounted on the bolt I98. In addition, a wear plate I91 may be interposed between the head of the bolt I98 and the inner surface of the cam wall I82.

Under impacts delivered to the main bar I of, the bumper there will be a deflection in the spring arms 4, the ends thereof accordingly sliding over the cam surfaces IBI. This sliding movement of the spring arm carrying the bolt I98 and plate spring I95 therewith, is resisted as in all the other previous cases described hereabove by a frictional resistance produced by the action of the spring plate I95 as well as the end wise resistance set up in the spring arm by its necessity in following the cam surface contour I8I as will be described in detail hereinafter.

The construction of Fig. 20 difiers essentially from that of Fig. 19 in that the slot is provided in the spring arm, the bolt being rigid with the cam member. In this case the cam wall I82 is provided with an opening I98 adjacent the outer end thereof adapted to register with the slot I99 formed in the end portion of the spring arm 4 I98 is the bolt 200. The head of the bolt is preferably found on its under surface with a cylindrical surface 20I on which the spring arm may have a somewhat rocking movement. To maintain the frictional engagement of the spring arm 4 on the cam wall I82 there is provided a rubber spring 202 on the bolt 200 and seated on the inner surface of the cam wall I 82. A plate member 203 is fitted over the rubber spring 202 which compresses the same and is thus retained by the pin 204. It is obvious that the rubber spring 262 may be replaced either by a plate spring such as I95, Fig. 19, or any other suitable spring element.

The construction shown in Figs. 21 and 22 is somewhat on the order of that disclosed in Fig. 19. The cam member 2I0 in this case is formed with a central depressed attaching portion 2| I, the bottom of which is in the same plane with the legs 2 I2 formed at the outer ends of the cam walls 2I3, said cam member being attached to the main bar I by the center bolt 2I4 and end bolts 2 I5. The longitudinal slot 2I6 formed in the cam walls 2 I3 is formed with outwardly tapered walls 2II, most clearly shown in Fig. 22'. As in Fig. 19 the spring arm 4 is provided adjacent its end with an opening 2 I8 in registry with the slot 2| 6. A bolt 2 I 9 provided with a wedge shaped head 22s having tapered sides adapted to cooperate with the tapered sides 2I1 of the slot 2I6, extends through said slot and opening 2| 8, and is provided with a plate spring 22I held under compression by the nut 222.

The mode of operation and results obtained in their form of construction is identical with the form shown in Figs. 19 and 20. The cooperating tapered sides in the bolt head 220 and sides 2|! of the slot 2I6 produce an automatic wear take up means to compensate for any wear taking place in the slotted connection. This construction furthermore acts to positively prevent any rattling of said parts of the bumper.

In much the same manner, the tapered slot and bolt head construction may be adapted to the form of connection wherein the slot is provided in the spring leaf, such for example as shown in Fig. 20.

In Figs. 23 and 24 the connection comprises a cam member 230 similar in structure to the cam member 2I0, in Fig. 21, and is attached to the main bar I by the centre bolt 23I and end bolts 232. Each of the cam walls 233 have formed thereon the longitudinal slots 234. The spring arm 4 is provided adjacent its end with spaced rectangular openings 236 and 231 of a width equal to the width of the slot 238 and arranged to register therewith, the end portion of said spring arm slidably engaging the cam surface 235.

Fitted within the slot 234 is a bearing clip 238 provided with spaced arms 239 of a width adapted to snugly fit within the openings 236 and 231 in the spring arm 4 and of a length to project for a distance therebeyond, for a purpose to be hereinafter described. The top or bight portion of the clip is formed with laterally extending bearing supports 240 having the shoulders 24I formed at each end thereon all as most clearly shown in Fig. 24. Disposed between the inner surface of the cam wall 233 and the bearing supports 240 of the clip 230 are a plurality of anti-friction roller bearings 242 which are retained in position by the shoulders 24 I. To maintain the frictional enga-gement between the spring arm 4 and the cam surface 235 there is positioned between the arms 239 of the clip a rubber spring 245 that is retained under an initially high compression by the retained cap 246 supported on the arms 239 and lockedthereto by the locking pin 241 or any other suitable means. If desired the rubber spring 245 may be replaced by any other type of suitable spring such as volute, helical or conical coil, or plate spring means. To support the arms 239 as well as the center portions of the rollerbearings there is positioned in the slot 234 between said arms the block 248, which may be of lubricant impregnated wood or metal.

In this form of connection it will be appreciated that the friction producing pressure set up by the rubber spring 245 is distributed over a wide area, the frictional resistance to the sliding of the spring arm 4 being restricted to the engaging surfaces of said spring arm and cam surface, in view of the roller bearing support of the clip 238 on the inner surface of the cam wall 233. In addition all rattling of parts is positively prevented.

In each of the forms shown in Figs. 19, 20, 21 and 23 the cam walls are shown of substantial thickness and rigidity and possess the additional function of a Wear plate.

The function and operation of the shock absorbing connection as embodied in the various forms above described will now be set forth with reference to the diagrammatic showing in Figs. 25, 26 and 27.

In Fig. 25 there is diagrammatically shown one half of a bumper showing a main bar I, a spring arm 4 comprising parts of the back bar 2 which is connected at one end to the main bar as at 3. The back bar being supported by the vehicle frame I. The free end of the spring arm 4 slidably engages a surface S on the main bar I and is disposed within the housing carried thereby. Within the housing and adjacent the spring arm end is the cam member provided with the cam surface 0. A resilient means It maintains the spring arm 4 in frictional engagement with the surface S. In the assembled bumper the normal relationship of the parts thereof is as shown in Fig. 25. When the main bar I is acted upon by the force of an impact designated F2,

the back bar 2 and spring arm 4 will'be dea fiected as shown in Fig. 26, the free end of the' spring arm 4 slidably moving on the surface S and on the cam surface C, the force acting within the bumper being that of the resilient means indicated Fr producing the force dynamic frictional resistance indicated Ffr and that acting against the end of the spring arm set up by the cam surface C and indicated Fc. In view of the deflection of the spring arm 4 as a result of the impact F2 in conjunction with the further deflection thereof produced as the end thereof is forced over the cam surface C, the additional forces indicated by the small arrows Fd are produced, which incidently increase by a substantial amount the force Ffr of frictional resistance.

It will be noted that as the end of the spring arm 4 is forced over the cam surface C that the spring arm 4 is so deflected thereby as to back up or flatten out along a substantial surface of the main bar I, which as indicated by the forces Fd act to reinforce the main bar I to the shocks of impact. The shock delivered by the force of impact F1 is thus effectively absorbed by the forces Ffr and Fe acting in opposition to the sliding movement of the spring arm 4 as well as by the forces FD which act in opposition to the force Fi that also reinforces the main bar I. It is apparent that the greater the deflection of the spring arm A the greater the forces Fe, Fri and Fjr will become.

In Fig. 27 there is hown diagrammatically the form of connection wherein the cam member 0 is replaced with a resilient means R, acting to resiliently oppose endwise movement of the spring arm 4. The force Fe, Fig. 26, is accordingly replaced by the force F'r, acting on the abutment formed on the end of the spring arm :5. The yielding resistance Fe to the inward movement of the spring arm 4 will produce the same flattening out effect on the spring arm 4 as described above, the connection thus functioning and operating in the same manner as that of Fig. 25.

The invention and manner of operation of the same having been described as above set forth, what I claim is:-

1. In a bumper provided with a spring arm member having an end portion' movably engaging a supporting element, and means carried by said supporting element and adapted to be engaged by the terminal end of said spring arm end portion, said supporting element having a portion of same for imposing an increasing progressive resistance to the endwise movement thereof in one direction of movement of the arm.

2. In a bumper provided with a spring arm member having an end portion slidably engag ing a supporting element, means carried by said supporting element for producing a frictional resistance to said sliding movement and including means disposed in the path of movement of said end portion for imposing a resistance to the end- Wise movement thereof in one direction.

3. In a bumper provided with a spring arm member having an end portion slidable relative to a supporting element, resilient means associated with said spring arm for producing a frictional resistance to said sliding movement and additional means carried by said supporting element for imposing a resistance to the endwise movement of said spring arm in one direction.

4. In a bumper comprising a supporting and a supported member, a spring arm carried by one of said members for sliding movement relative to a surface of the other, means associated with said spring arm for producing a frictional resistance to said sliding movement and including sequentially operative means for resisting endwise movement thereof in one direction.

5. In a bumper, a pair of opposed spring elements adapted for sliding movement on a surface of a supporting member, resilient means associated with each of said spring elements for producing a frictional resistance to said sliding movement and means operative between said spring elements for resisting endwise movement thereof towards each other.

6. In a bumper comprising a supported member and a supporting member, a spring arm carried by one of said members having upon deflection of the same an end thereof adapted for movement relative to the other of said members, and means carried by said last mentioned member arranged in the path of movement of said spring arm end for additionally deflecting the same to impose a resistance to said endwise movement.

7. In a bumper comprising a supported member and a supporting member, a spring arm carried ment relative to the other of said members, and abutment means carried by said last mentioned member arranged in the path of movement of said spring arm end for additionally deflecting the same to impose a progressively increasing resistance to said endwise movement.

8. In a bumper comprising a supported member and a supporting member, a spring arm carried by one of said members having upon deflection of the same an end thereof adapted for sliding movement relative to the'other of said members, means providing a cam surface carried by said last mentioned member and arranged in the path of movement of said spring arm end for defleeting said end away from said last mentioned member whereby there is imposed a progressively increasing resistance to said endwise movement.

9. The structure specified in claim 8, and resilient means associated with said spring arm end for producing a frictional resistance to the sliding movement of the same.

it. In a connection between two elements of a bumper at least one of which is resilient and formed with an end portion having slidable movement relative to the other comprising a supporting member carried by the other of said elements having a surface normally engaged by said end portion, spring means mounted on said supporting member and associated with said end portion forproducing a frictional resistance to the initial sliding movement thereof on said surface and sequentially operative means arranged in the path of movement of said end portion for imposing an additional resistance to the endwise movement thereof.

11. In a bumper'provided with a spring arm member having an end portion slidably engaging a supporting element, resilient means associated with said end portion for roducing an initial frictional resistance to said slidable movement and a cam surface so constructed and arranged as to be slidably engaged by the end of said spring arm after a mediator ined movement thereof to impose an additional resistance to said slidable movement.

12. In a bumper provided with a spring arm having an end portion thereof slidably movable on a supporting element upon deflection of said spring arm, a cam member carried by said supporting element and provided with a cam surface so constructed and arranged as to he slidably engaged by the end of said spring arm end portion whereby a resistance to said movement will be imposed thereon as to additionally deflect said spring arm to provide a progressive engagement of said spring arm with said supporting element.

13. The structure specifiedin claim 12, and re silient means associated with said spring arm end portion for producing'an initial frictional resistance to the sliding movement thereof.

14. In a bumper comprising a main bar a back bar, a spring arm carried by said back bar and under deflection thereof adapted to have an end portion slidably movable relative to said main bar, means connecting said spring arm end portion to said main bar comprising a cam member secured to said main bar and provided with a surface, a portion thereof being disposed substantially parallel to said main bari and normally engaged by said spring arm end, the remaining portion of said surface being curved away from said main bar to define a cam surface adapted to be engaged by said spring arm end upon movement thereof whereby there is produced a resistance to the endwise movement of said spring arm end to cause an additional deflection of said spring arm.

15. In a bumper comprising a supporting member and a supported member, a spring arm element carried by one of said members and having an end thereof adapted for slidable movement relative to said other of said members, a cam element carried by said last mentioned member provided with a surface adapted to be engaged by the end of said spring arm element, a longitudinal slot in one of said elements, a connecting means carried by the other of said elements arranged for sliding movement in said slot, and resilient means carried by said connecting means for maintaining said elements in frictional engagement, the portion of said surface adjacent the end of said spring arm element in the normal position thereof defining a cam surface of such a curvature as to impose a resistance to the endwise movement of the end of said spring arm element.

16. In a connection between two elements of a bumper at least one of which is resilient and formed with an end portion having slidable movement relative to the other comprising a member carried by the other of said elements provided with a surface normally engaged by the end portion of said resilient element and including a cam surface adjacent said end portion arranged in the path of movement of the same to impose a resistance to the endwise movement thereof, and. cooperating guide means positively connecting said end portion to said member including spring means for maintaining the same in frictional engagement with said surfaces and to produce a frictional resistance to the movement thereon.

17. In a connection between two elements of a bumper at least one of which is resilient and formed with an end portion having slidable movement relative to the other comprising a member carried by said other element provided with a surface normally engaged by said end portion, resilient means mounted on said member and arranged in the path of movement of said end portion to resiliently resist said movement, said end portion having associated therewith spring means to maintain the same in frictional engagement with said surface.

18. In a connection between two elements of a bumper at least one of which is resilient and formed with an end portion having slidable movement relative to the other comprising a member carried by said other element provided with a surface normally engaged by the end portion of said resilient element and an additional cam surface .adjacent said end portion arranged in the path of movement of the same to impose a resistance to the endwise movement thereof, said end portion having associated therewith spring means to maintain the same in frictional engagement with said surfaces.

19. In a connection between two elements of a bumper at least one of which is resilient and formed with an end portion having slidable movement relative to the other comprising a housing member carried by said other element having therein a surface normally engaged by said end portion, a cam surface supported within said housing member and arranged in the path of movement of said end portion to impose a resistance to the endwise movement thereof and spring means mounted within said housing member and associated with said end portion to maintain the same in frictional engagement with said surfaces.

20. In a connection between a main bar of a bumper and a pair of spring arms having opposed end portions arranged for sliding movement relative to said main bar and towards each other comprising a housing member carried by said main bar having therein a surface normally engaged by each of said end portions, a cam member supported within said housing having a pair of cam surfaces each arranged in the path of movement of an adjacent end portion to impose a resistance to the endwise movement thereof and spring means mounted within said housing for association with each of said end portions to maintain the same in frictional engagement with said surfaces and to produce a frictional resistance to the movement thereon.

21. In a bumper, a main bar, a back bar commovement of the ends of said spring arms for a resisting endwise movement thereof.

22. In a bumper provided with a main bar, a back bar comprising a pair of spring arms, each spring arm being connected at one end to the main bar, the other ends of said Sp ing arms being .arranged in opposed relation for sliding engagement with a surface on said main bar, resilient means associated with each of said opposed ends for producing a frictional resistance to said sliding movement and means operative 1 in the'path of movement of said opposed ends for resisting endwise movement thereof.

VILLOR P. WILLIAMS. 

